Placement in an old apartment (built in 1980) in Athens, 90 sqm, with many losses (no thermal insulation and old aluminum frames). A total of 5 units were installed for full coverage, as follows: 3 in the open space living room-dining room-office with a total area of 35-40 sqm (1000W, 1500W, and 2000W) and 1 (1500W) in each bedroom (12 sqm each). The results are amazing! Firstly, the heating quality is equivalent to a radiator. A beautiful and clean warmth that makes you feel incredibly comfortable! With the electronic thermostat set conservatively at only 20 degrees and after continuous operation for about 30 minutes to 1 hour, an average temperature of 21-22 degrees is achieved and maintained. On weekdays, the bedroom units operate for about 12-14 hours (from the moment we return home from work until the whole night), while the living room units operate for about 8 hours (only while we are awake, as they turn off during the night). On weekends, all units operate for almost the entire day while we are at home (18-20 hours) and turn off when we go out for a walk. Generally, the key to achieving maximum efficiency is to only turn them on where and when needed. Of course, for greater convenience, it is recommended to connect them to the power supply through smart plugs, so that remote control is possible (e.g. to be able to turn them on while on the way home, so that we find the house warm when entering, and also to be able to regularly measure and monitor consumption). Based on the above operating plan, we consume about 400-500 kWh per month (maximum 600), which with an average final price of 0.22 euros/kWh (in the DEH G1N Residential program) means that our heating costs are limited to about 130 euros. Not bad at all, considering that last year, heating with natural gas cost us 300 euros and more per month! Same (and better) heating result at half the cost! This is also due to the fact that these heaters incorporate heat accumulation technology. That is, while they are operating, they cyclically store a small amount of energy, which is then released as heat without needing to consume electricity all the time. Moreover, we expect even greater savings soon, as we are in the process of replacing our old windows! Attention! In order for all units to operate simultaneously in a house with a single-phase power supply (8kVA), an increase in power to an enhanced single-phase (12kVA) is required, with the corresponding cost of course (DEDDIE works and electrician. Calculate a total cost of about 700-800 euros). In conclusion, I would like to emphasize that I put a lot of thought into this heating method before deciding on it, which, by the way, does not require complex installation (simple wall mounting with screws and voila, provided in the package) or annual maintenance (like, for example, a heat pump). Plug and play, so to speak... Finally, the choice of these specific Technotherm heaters was made taking into account their German technology and excellent construction quality, which fully justifies their somewhat higher purchase price compared to other heating systems. In my opinion, it is a worthwhile investment!